JPS5920438B2 - Screw press dehydrator with cake cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a screw press dehydrator used for dewatering sewage sludge, various industrial wastewater sludge, etc., or solid-liquid separation in the manufacturing process of various products.

More specifically, the cake that is dehydrated by being pressed in the axial direction of the screw cylinder by the screw is repeatedly expanded in the circumferential direction of the screw cylinder and pushed back inward while applying this axial pressure. This article relates to a screw press dehydrator equipped with a cake cutter that improves dewatering efficiency.

Conventionally, a screw press dehydrator equipped with a cake cutter has a fixed plate with a circular hole near the discharge port of the screw cylinder, and an ellipse with both ends formed by arcs with the same diameter as the circular hole of this fixed plate. A large number of sliding plates with holes are arranged alternately by passing screws through the matching holes, and the sliding plate is placed between the positions where the arc of the end of the oblong hole of the sliding plate and the circular arc of the circular hole of the fixed plate overlap. A device in which a plate is slid back and forth in the long axis direction of its oblong hole is known (Japanese Patent Publication No. 156-1987).

According to the screw press dehydrator equipped with the cake cutter, the cake is pressed in the axial direction of the screw cylinder as the screw rotates, and the sliding plate reciprocates,
It is possible to repeat the process of expanding the cake in the circumferential direction of the screw cylinder in the oblong hole of the sliding plate and pushing the expanded cake back inward again, which improves the dewatering efficiency compared to the case where the cake is simply suppressed by the screw. can be improved.

In other words, the moisture in the deep part of the cake does not easily move to the surface and is difficult to separate, but when the cake is repeatedly expanded and pushed back, the vibration action promotes the movement of the moisture in the deep part of the cake to the surface, which results in dehydration. Efficiency is improved.

However, in the screw press dehydrator equipped with the cake cutter mentioned above, the cake swells and pushes back intermittently in alternating vertical and horizontal directions due to the reciprocating movement of the sliding plate, which causes the cake to pulsate violently and retain moisture. There is a drawback that leakage of solid content from the gap between the fixed plate and the sliding plate for discharging is severe.

Moreover, the impact caused by this rapid pulsation of the cake shortens the life of the device.

Furthermore, since the cake expands and pushes back only in one direction, up and down or left and right, the moisture in the deep part of the cake cannot be moved uniformly to the surface throughout the cake, and there is still a long way to go to improve dewatering efficiency. There is still room for improvement.

On the other hand, a large number of fixed plates and sliding plates having circular holes of the same diameter are arranged alternately near the discharge port of the screw cylinder, with screws passing through the matching holes, and the circular holes of the fixed plate and sliding plate are arranged alternately. There is also known a device in which a sliding plate is tilted back and forth while keeping the centers aligned (Japanese Patent Publication No. 581919).

However, the above-mentioned screw press dehydrator only tilts the sliding plate back and forth to prevent the gap between the fixed plate for draining water and the sliding plate from clogging. Since this machine does not have the function of expanding and pushing back the cake, it is inferior in terms of dehydration efficiency even compared to the screw press dehydrator equipped with the cake cutter described above.

The present invention solves the above-mentioned conventional drawbacks, and aims to provide a screw press dehydrator equipped with a cake cutter that can continuously and uniformly expand and push back the cake from the entire circumferential direction. It is.

This object of the present invention is to make the holes of the fixed plate and the sliding plate into circular holes in which the hole diameter of the sliding plate is larger than the hole diameter of the fixed plate,
In order to keep the outer periphery of the circular hole in the fixed plate in contact with the outer periphery of the circular hole in the sliding plate, the sliding plate slides in a circular motion such that the center of the circular hole in the sliding plate draws a circle with a constant diameter around the center of the circular hole in the fixed plate. This is achieved by applying a force to the sliding plate so that the direction in which the cake expands and is pushed back again within the large-diameter circular hole of the sliding plate can be successively changed over the entire circumferential direction of the screw cylinder.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

As shown in FIG. 1, a screw 3 passes through the screw cylinder 1 and is supported at both ends by bearings 2a and 2b.

This screw 3 is rotated via a drive gear 4.

On the left side of the screw cylinder 1 in the figure, an input port 5 is provided for charging the material to be processed into the screw cylinder 1.

Further, the right end of the screw cylinder 1 in the figure serves as a discharge port 6 for discharging the cake after dewatering.

This discharge port 6 is connected to the screw tube 1 by a spring 7.
It is closed by a sliding boss 8 that is pressed toward the side, and the object to be treated is compressed and dehydrated by the forward force generated by the rotation of the screw 30 and the pressing force of the spring I that presses the sliding boss 8.

Then, the cake that has been dehydrated is pushed back against the spring 7 by the advancing force, and the discharge port 6 is pushed open and pushed out one after another. It is discharged from the gap between the sliding plates 10a and 10b.

The above configuration is similar to the conventional screw press dehydrator, but the screw press dehydrator equipped with the cake cutter according to the present invention has a large number of screw press dehydrators provided near the discharge port 6 of the screw tube 1, which is also the drainage section. fixed plate 9 and sliding plate 1
0a and 10b have major characteristics.

This will be further explained below.

The fixed plate 9 and the sliding plates 10a and 10b each have a circular hole 1L12, and a screw 3 is passed through each circular hole 11°12, and a large number of screws 3 are provided alternately near the discharge port 6 of the screw cylinder 1. It is being

As shown in FIGS. 1 and 2, the fixed plate 9 is fixed to brackets 14 provided at the front and rear by means of support shafts 13 passing through its four corners.

As shown in FIGS. 2 and 3, the sliding plates 10a and 10b have both sides projecting laterally from the fixed plate 9, and are each connected by four connecting shafts 15 passing through the projecting portions. are integrally connected.

Moreover, the sliding plates 10a at both the front and rear ends are different from the sliding plate 10a at the middle part.
Both sides project further laterally from b, and circular cam holes 16 are formed in each of the projecting portions.

A circular cam 17 that idles in the cam hole 16 is loosely inserted into the cam hole 16, and the rotating shaft 1B to which the cam 17 is eccentrically fixed is fixed to the bracket 14. It is supported by a bearing 2ct2d and rotated via an operating gear 19.

Therefore, when the rotating shaft 18 rotates and the cam 17 idles in the cam hole 16, the sliding plates 10a and 10b
The centers of the circular holes 12 in a and 10b are aligned with the cam 17 and the rotating shaft 18.
This results in a circular motion that draws a circle whose radius is the length corresponding to the amount of eccentricity between the two.

As mentioned above, the holes in the fixed plate 9 and the sliding plates 10a and 10b are circular holes 11 and 12, respectively, but as shown in FIG. It is larger than the diameter of the circular hole 11 of No.9.

The fixed plate 9 and the sliding plates 10a and 10b are
The outer periphery of the circular hole 11 and the sliding plate 10a.

The circular hole 11 is in contact with the outer periphery of the circular hole 12 of 10b at one point.
The center of the circular hole 12 and the center of the circular hole 12 are eccentrically provided, and the circular movement of the sliding plates 10a and 10b always moves toward the circular hole 1.
1 and the circular hole 12 are made in contact with each other at one point.

That is, as shown in FIG. 4, the center X of the inner circular hole lL12
, x The eccentricity T of the kidney is equal to the eccentricity γ between the centers Y and r of the cam 17 and the rotating shaft 18, and when the cam 17 rotates, the center X of the circular hole 11 is the center of the circular hole. At the center of 12, there is a sliding movement that draws a circle with a radius corresponding to the eccentricity T between the inner circular holes 11 and 12 (same as the eccentricity T' between the cam 1T and the rotating shaft 18). This is provided to the moving plates 10a and 10b.

Next, the effects of the present invention will be further explained with reference to FIG.

As shown in the figure, when the sliding plate 10a (10b) and its circular hole 12 are in the position shown by the solid line, the lower end of the circular hole 12 is in contact with the lower end of the circular hole 11 of the fixed plate 9, and the circular hole 12 is in contact with the lower end of the circular hole 11 of the fixed plate 9. Hole 12
The upper end is located further above the upper end of the circular hole 11, thereby creating a space 20 above.

Further, the cake being pressed by the screw 3 expands and enters this space 20.

Next, the sliding plate 10 at (10b) moves circularly as described above, and the sliding plate 10a (10b) and the circular hole 12 move to 10a'(10b') shown by the broken line in the figure. When moving to the position 12', the space 20 is located at 20 to the right of the circular hole 11.
’.

At this time, the cake that had entered the space 20 is pushed back inward with the movement of the sliding plate 10a (10b), and a new cake enters the space 20' due to the pressing force of the screw 3. become.

Therefore, the cake that is being compressed in the axial direction by the screw 3 is simultaneously repeatedly expanded and pushed back in the circumferential direction, and this vibration action causes moisture in the deep part of the cake to move to the surface. Water separation is promoted and dehydration efficiency is improved.

In addition, the cake, as it expands and pushes back, exposes a new surface to the inside of the device, and the constant change in the surface of the cake from which water tends to separate also promotes dehydration.

Swelling and pushing back of the cake is done by the sliding plate 10a.

Since the dehydration is carried out continuously over the entire circumference along with the circular motion of the drain 10b, the entire cake can be dehydrated uniformly, and the pulsation of the cake is also extremely small. Moving plate 10a.

There is no risk that a large amount of solid content will leak out from the gap between the parts 10b or that the life of the device will be shortened due to the impact of pulsation.

The reason why there is almost no pulsation in the cake is that when the cake is expanded and pushed back intermittently as in the conventional method, a load is intermittently applied from the circumferential direction to the advancing cake by the screw 3. In contrast, in the present invention, the load applied to the cake from the circumferential direction is constant and continuous.

The number of fixed plates and sliding plates in the present invention may be appropriately determined in consideration of the size of the device and the like.

Normally, about 10 to 30 sheets for both machines.

In what is shown in the drawings, the front and rear two sliding plates are interlocked with the rotating shaft, but all sliding plates may be interlocked with the rotating shaft.

In this case, instead of ensuring that the circular holes of all sliding plates are always in the same position with respect to the circular holes of the fixed plate, as shown in the figure, the circular holes of each sliding plate should be aligned with the circular holes of the fixed plate. It may also be arranged that the cake is at a position that is slightly shifted from the center, so that the cake is expanded and pushed back radially at the same time.

For this purpose, the eccentric direction between the centers of the circular holes of the fixed plate and the sliding plate and the eccentric direction between the centers of the cam and the rotating shaft may be slightly shifted between each sliding plate.

In this way, the cake is expanded and pushed back radially at the same time, which is more effective in promoting dehydration.

It is preferable that the circular motion of the sliding plate be made in the same direction and synchronously with the rotation of the screw.

This is to prevent the forward movement of the cake by the screw from being obstructed.

Next, an example of the use of the screw press dehydrator according to the present invention will be explained while comparing it with a conventional product.

The product of the present invention is as explained in FIGS. 1 to 4, and its specifications and operating conditions are as follows.

Screw cylinder inner diameter 250m711 Screw cylinder length 1800r/111
Number of L multi-plates 22 sets Multi-plate part gap 0.1 to 0.2 mu Rotational speed of sliding plate
3 times/min screw rotation speed
A conventional product that operates 12 to 13 times per minute is as shown in Japanese Patent Publication No. 156-1983, and its features and operating conditions are as follows.

Screw cylinder inner diameter 155mm Screw cylinder length 1700mm Multi-plate
Number 22 pairs multi-plate gap
0.1~0.2mm sliding plate sliding speed
15 reciprocations/min Screw rotation speed 12-13
The following table shows the results of dehydration of pig manure using the product of the present invention and the conventional product as described above.

In addition, as the sliding speed of the sliding plate of the conventional product is lowered, the solid content recovery rate increases to some extent, but the water content of the dehydrated cake tends to increase.

Further, while the conventional product had two failures in the reciprocating sliding drive portion of the sliding plate during one year of use, the product of the present invention did not have any failures during one year of use.

As explained above, according to the present invention, it is possible to simultaneously expand and push back the cake in the circumferential direction of the screw cylinder, which is compressed in the axial direction of the screw cylinder. Since the output and push-back are performed continuously over the entire circumference, a screw press dehydrator equipped with a cake cutter with uniform dehydration and less pulsation can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a side vertical cross-sectional view showing an embodiment of a screw press dehydrator equipped with a cake cutter according to the present invention, Fig. 2 is a longitudinal cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a vertical cross-sectional view taken along FIG. 4 is an explanatory view of the effects of the present invention. 1...Screw tube, 3...Screw, 9...
Fixed plate, 10a, 10b...Sliding plate, 11...Circular hole in fixed plate 9, 12...Circular hole in sliding plate 10a, 10b.

Claims (1)

[Scope of Claims] 1. A fixing plate 9 and a sliding plate 10at10b having holes are placed near the discharge port 6 of the screw cylinder 1, and a screw 3 is inserted into the matching hole.
In a screw press dehydrator in which a large number of holes are arranged alternately through the fixed plate 9 and the sliding plates 10a and 10b, the sliding plate 10a has holes. A circular hole 12 in which the diameter of the hole 10b is larger than the diameter of the hole in the fixing plate 9.
and the outer periphery of the circular hole 11 of the fixed plate 9 and the sliding plate 10atlOb
The center of the circular hole 11 and the center of the circular hole 12 are made eccentric so that the outer periphery of the circular hole 12 touches at one point, and the fixed plate 9 and the sliding plate 10a are
. A screw press dehydrator equipped with a cake cutter, characterized in that the cake cutter is attached to sliding plates 10a and 10b.